The present invention relates to an information processing device having an initial screen image, its control method and a recording medium holding a record of control processing procedure and, more particularly, to an information processing device having both functions for returning a screen image to a preceding state and to an initial screen, a control method of the device and a recording medium holding the control program.
Many kinds of conventional information devices including portable information terminals have a predetermined initial image presentable just after turning on its power supply or driving a browser software for communication over the Internet. The presentation of such a fixed specified initial screen image is intended to give a user sense of relief and convenience for operation.
Known techniques to realize the above are as follows:
(1) To give a user feeling of relief, many browser softwares provide a function for returning from any current screen image to a specified initial screen image by operating a functional key "HOME" any time irrespective of current conditions. On the other hand, it has been also realized that a user can return from any current state to a preceding state by using a specially designated "RETURN" key in case of having made an error in key operation or re-confirming the preceding state.
(2) In distinction from the above method using two different keys for driving respective functions, there also exists an alternative method for driving two respective functions by using one designated key only and together with, e.g., a "SHIFT" key.
Furthermore, techniques for switching-over two functions "return to an initial screen" and "return to a preceding state" are disclosed in (3) Japanese Laid-Open Patent Publication No. 4-139511 and (4) Japanese Laid-Open Patent Publication No. 8-137846.
(3) The technique disclosed in Japanese Laid-Open Patent Publication No. 4-139511 is such that an information processing device provided with a timer means and a presetting means measures an elapse of time for which no key-operation was made and, when a time counted by the timer means meets with a time duration preset by the time-presetting means, automatically makes a backup copy of the current content and returns to an initial screen.
(4) The technique disclosed in Japanese Laid-Open Patent Publication No. 8-137846 is such that an information processing device which is a word processor with a sentence-backup function and is provided with a passing-time measuring means and which measures an elapse of time for which no key-operation was made, discriminates whether the elapsed time reaches a preset time and, if so, it forcibly registers sentences edited up to that moment in a backup area, clears the current screen and returns to an initial screen.
However, the above-described arts involve the following problems:
The prior art (1) uses two different keys "HOME" and "RETURN" which enables a user to return to the initial screen or the preceding state anytime. However, the provision of two different keys is inconvenient in common for small-size information processing devices having a limited space for control elements. Each of the keys must have a reduced size and difficult to operate.
The prior art (2) must use two keys (one designated key and the SHIFT key) at a time for driving the second of two functions in principle. In a small information processing device, the operation of two small keys at a time is not easily done.
The prior art (3) is intended to a device that can set a time duration and, if no operation on a keyboard is made for the preset time, automatically makes a backup copy of a content of the current operation (i.e., a current processing content) and returns to the initial screen. It discloses merely the above and does not suggest means and method for returning to a preceding state.
The prior art (4) is directed to a device that, if no operation was made on a keyboard, automatically makes a backup copy of a current content (sentences being currently edited) and returns to the initial screen. It discloses merely the above and does not suggest means and method for returning to a preceding state.